Fuel pump



March 28,1933. J. ZUBA TYQ 1,902, 30

FUEL PUMP Filed Mrch 9.192s

' dual/w 30 of Figure Patented' Mar. 28, 1933 UNITED STATES JosninZUIBFATY, or FLINT, :nncmem FUEL ruin],-

: Application filed.ll[arch 9,

Thisinvention is concerned with the fuel supply for an internalcombustion engine and particularly for an engine employing asupercharger and one wherein the fuel is supplied to the carburetor byan engine operated fuel An object of the invention is to provide animproved fuel pump for use with an internal combustion engine havingassociated therewith a supercharger placed beforethe carburetor andcompressing air only. More specifically, the invention provides a pumphaving a discharge stroke the efliciency of which is made variable andwhichefliciency is automatically. changed to supply fuel to thecarburetor at a pressure dependent upon the air pressure delivered tothe carburetor by the supercharger. Other objects and advantages will beunderstood from the following description and from an examination of theaccompanying drawing.

In the drawing: Figure 1 is a side'elevation of an internal combustionengine, such as is used on mo-" tor vehicles, the engine having myimprovements associated. therewith.

Figure 2is a vertical. section through parts of the fuel supply system.c

Figure 3 is a horizontal section on line 33 Referring by referencecharacters to'the drawing, numeral 5 is used to designate an internalcombustion engine. The invention is concerned only with the fuel systemfor the .35 engine and other parts will not be included in thisdescription. Numeral7 is usedto,

designate an intake manifold and 9 a header therefor connected to acarburetor 11 by fastening means 13.

An-air cleaner 15 of any preferred kind maybe used. If such an aircleaner is used, it will be connected to a supercharger 17 fordelivering air to. the carburetor. The structure of this superchargerneed not be de- 4 scribed as the details of'the supercharger are.

matter ofthis invention is used in connection 1928. Serial No. 260,419.

no part of this invention. The supercharger draws air through thecleaner 15, if such cleaner is used, and deliversthe air atsuperatmospheric pressure to the air inlet tube 23 of the carburetor 11,the air under high pressure passing through the header 9, manifold 7 andinto the engine cylinders.

In such a system, the pressure in the ven-; turi of the carburetor maybecome sufficient, 1y high to oppose the flow of fuel from the floatchamber. This difiiculty is remedied by I sealing the float chamber 21and connecting the. sealed float chamber with the air tube 23 of thecarburetor by asuitable conduit 19 as shown in Figure 1. This provisionas-.

sures an ample fuel flow even when the-pressure in tube 23 is aboveatmospheric.

Numeral 25 represents a fuel pump having a diaphragm 27 confined betweenbody 29 and its cover 31. The cover 31 is preferably ex- 05 tendedbeyond the pump body and to the extension may be secured a filter cup33.. A

bail 35 is attached to the cover'extension and surrounds the cup 33. Ascrew eye 37 hasits eye portion encircling the bail beneath the cup 33and an adjusting nut 39 may be threaded up on the threaded part of the lscrew "eye to hold firmly against theb'ottom of the cup a support 41This is described as a convenient and preferred form of cup supportbut'these details do not form a part of this invention.

The cover 31 has an inlet 43 communicating with the fuel-reservoir.'When the subject with motor "vehicles, the fuel reservoir willobviouslybe the tank usually carried in a low position at the rear of thevehicle. From the inlet 43 and angular passage 45 conducts the fuel toan opening or openings 47 communicating with the interior of the fuelcup and beneath suitable filtering. means 49.

Filtered by said filtering means, the fuel may pass an inlet valvedesignated by numeral 51 and preferably located in the cover mem- 90ber. From valve 51 the fuel passes through passage 53 to the variablevolume pm chamber of the pump 25. This chamber is constituted by theflexible diaphragm 27 and the outer 31. An outlet valve 55 of anypreferred form is also located preferably in the cover member 31 andcontrols a discharge from the pump chamber to the pipe 57 leading to thefloat chamber of the carburetor.

The diaphragm'27 is reinforced by discs 59 and connected by a rod 61with a collapsible link member 63 to be connected to suitable operatingmeans. This operating means may be of some other type but is preferablyin the form of a lever pivoted to the pump body, one end of the leverengagingtheblower end of the collapsible link and the other end of thelink actuated by-the cam of the camshaft. This construction is notillustrated as it is well-known and constitutes no part of thisinvention. By this arrangement, the operating means may through the.instrumentality of the collapsible link, pull down upon the diaphragm tomake a suction stroke. The.

discharge stroke is preferably made by a coil spring 65 engaging thelower disc 59 and also an abutment in the pump body. In the usual use ofsuch a pump where no supercharger is employed, the lower abutment forspring 65 is fixed. In the present form, however, an automaticallyvariable lower abutment is made use of as described below. In use, the

collapsible link pulls down upon the diachamber sealed and undersuper-atmospheric pressure, the discharge operating spring 65 of pump 25may not be sufliciently effective to overcome the pressure in the floatchamber which the pumpsupplies. This inventionhasb 11 made to correctthis difficulty by givi g to spring 6'5 added efficiency in proportionto the added burden to which it may be subjected. To this end instead.of providing a fixed abutment beneath spring 65, there is a variableabutment. A lower" disc 67 has an upper cam surface en aging a similarcam surface on the lower ace of an upper cam disc'69. The spring restson the up er disc '69. Means are provided to rotate isc 69 on' disc'67'to thereby raise the lower spring abutment and add to its effectivepressure in producing the discharge stroke of the pump. Toaccomplish'this purposev the upperdisc is provided with a radial nected to tone endof link 73. I The cover 77 is provided with an opening 91 to which issecured the end of a conduit 93, which also communicates with theairtube 23 of the carburetor. By this means, the air pressure in the airtube 23 is communicated to the chamber defined by cover 77 and diaphragm81. One or more breather-openings 95 are provided in the chamber 75 tokeep the air therein at atmospheric pressure and'make possible a flexingof the diaphragm 81 with changing pressures in the air tube of thecarburetor. A spring 97 is placed on the atmospheric side of diaphragm81 to return the diaphragm to its former position after being movedinlwardly by air pressure. It will be under stood that such inwardmovement recipro cates plunger 83'and link 73 and rocks disc 69 upondisc 67 whereupon the cam surfaces cause. the rising of the lowerabutment of spring 65. As a result spring 65 is rendered more effectivein overcoming the fluid pressure in the pump chamber and thereby moreeffective in dischargingffuel from the pump to the sealed float chamberof the carburetor.

'It will be understood that simultaneously with increased ressure in thefloat chamber due to pipe 19 t e pressure on diaphragm 81 is increasedand spring 65 is given additional efficiency to deliver fuel to thecarburetor.

While but one mechanical connection between the lower spring abutmentand the control chamber 75 is herein described, it will beof courseunderstood that other connections to accomplish the same result may beresorted to. A double arm lever, for examle, might'be pivoted to thepump chamber avingone arm actuated by the connected link 73,and theother operable to raise the movable abutment for spring 65. Numerous 4other expedients will be obvious.

By the arrangement described, there is pro vided a fuel pump operable byresilient means on its discharge stroke and which resilient means isrendered automatically va riably efi' ective in proportion to theVariable need for a discharge stroke dependent upon the pressure in asealed float chamber. The result is accomplished by'means both simpleand inexpensive.

Iclaim:

1. In a. fuel supply system for internal combustion engines, acarburetor having a sealed float chamber. 'nd an .air inlet, a su-"percharger delivering air ugler pressure to said air inlet, a condu'itfrom said air inlet to said float chamber, a pump having ayieldingmember to effect a discharge stroke, a

movable abutment therefor, a variable vollune chamber, a conduittherefrom to said air inlet, a plunger reciprocable by air pressure insaid chamber, said plunger operably connected to said variable abutmentwhereby the potential energy of the yielding member is modified bymovements of the plunger.

2. The invention defined by claim 1, said movable abutment comprisingamovable cam member, a fixed cam member in engagement therewith, thefirst-named cam member serving as an abutment for the yielding member.

3. The invention defined by claim 1, said movable abutment comprising arotatable disc having a cam face, a fixed disc having a co-operating camface, said first-named disc serving as an abutment for said yieldingmember and provided with an arm, said plunger connected to said arm.

4. In a fuel supply system for internal combustion engines, a carburetorhaving a sealed float chamber and an air inlet, a super- 1 chargerdelivering air under pressure to said air inlet, a conduit from said airinlet to said float chamber, a variable stroke pum delivering fuel tosaidfloat chamber, sai pump comprising a collapsible linkage to effectthe suction stroke and a sprin to effect the dis charge stroke wherebytfie length of the stroke is dependent on the pressure in the floatchamber, amovable abutment for said spring to var the pressure exertedthereby during the dlscharge stroke, and means to v automaticallycontrol the position of said abutment by the air pressure in thecarburetor air inlet.

5. In a fuel supply system for internal combustion engines, a carburetorhaving a sealed float chamber and an air inlet, asuperchargerrdelivering air under pressure to said air inlet, a conduitfrom said air inlet to said float chamber, a variable stroke pumpdelivering fuel to said float chamber, said pump comprising lost motionmeans to effect the suction stroke and yieldin means to effect thedischarge stroke where y the length of the stroke is dependent on thepressure in the float chamber,'a movable abutment for said yieldingmeans to vary the pressure exerted thereby during the discharge stroke,

and means to automatically control the position of said abutment by theair pressure in thecarburetor'air inlet.

6. In a fuel supply system for internal combustion engines, a carburetorhaving a sealed float chamber and an air inlet, means to supply airunder pressure to said air inlet, a conduit from said inlet to saidfloat chamher, a fuel pump, a conduit from said pump to said floatchamber, said pump having yielding means as the sole agency to efiect aplunger operably connected to said movable abutment.

In testimony whereof I aflix my signature.

JOSEPH ZUBATY.

